1. Field of the Invention
The present invention relates to an image forming apparatus provided with an image reading unit.
2. Related Art
Currently, an image reading device such as an image scanner is not only used alone but also widely used in a state of being embedded in a copy machine, a facsimile machine, a printer, an image forming apparatus called a digital multifunction peripheral having functions thereof, and the like. In a case in which the image reading device is used alone, for example, the image reading device is connected to a PC (personal computer) via a cable. An image that is read is submitted from the image reading device to the PC in a form of data, and thereafter the PC reproduces the image.
As such an image reading device, an image reading device has been known that is a substantially a read only device for reading a relatively small-sized card type original including a business card and a postcard, and that reads for example a graphical image such as a corporate logo, characters and numbers such as address, name, telephone number, fax number and the like printed on a business card and submits to a PC in a form of image data.
In general, image data captured by the image reading device is extremely high in data volume compared to other types of data. Therefore, in a case of successively reading a plurality (a large number) of business cards or cards and successively submitting image data to a PC in real time, a conventional method takes a long time and is inefficient. The above-mentioned image reading device is improved to increase efficiency by employing the following method.
The image reading device of the related art 1 first reads image data on an original surface by scanning and identifies and separates each part of the image data as character data and graphical data. More specifically, the image reading device recognizes an image being read as character data if tones of the image are represented by two-valued data or black-and-white data, and as graphical data if tones of the image are represented by multivalued data with at least 3 tones, or by color data. Thereafter, the image reading device transfers the character data thus identified in a bulk transfer mode and the graphical data thus identified in an isochronous transfer mode to a PC.
In the abovementioned method, the bulk transfer mode, in which the PC can request retransmission in a case of transmission error although immediacy of transfer cannot be expected, is suitable for character data transfer that requires confirmation of content while not requiring a high data transfer rate. On the other hand, the isochronous transfer mode guarantees data transfer rate while not handling data transfer error, thereby efficiently transferring the graphical data with high data volume. Transfer time between the image reading device and the PC is thus reduced.
Here, not limited to the abovementioned image reading device, a copy machine, a facsimile machine, a printer, and a multifunction peripheral having a function of storing image data of an image store a complete set of the image data to a storage medium provided in an apparatus main body or to an external storage medium such as a PC. From a point of view of security, this means that contents of the original thus stored can be stolen from the apparatus main body or the external storage medium, and that, in some cases, confidential information included in the original may leak to the outside and the original may be copied by a third party.